A technique for a management apparatus to manage a transmission network including plural transmission apparatuses has been proposed. According to the technique, when a failure such as a disconnection between the transmission apparatuses develops in the transmission network, for example, a transmission apparatus adjacent to a failure development location detects a loss of signal (LOS). The transmission apparatus that has detected the LOS notifies the management apparatus of that effect as an alarm. A transmission apparatus other than the transmission apparatus that has performed the notification of the LOS detection detects an alarm indication signal (AIS) or a remote defect indication (RDI) on the basis of the detection of the LOS. The transmission apparatus that has detected the AIS or the RDI notifies the management apparatus of that effect as an alarm. The management apparatus is notified of a large amount of alarms in this manner.
Techniques for reducing loads on the management apparatus with respect to the alarms have also been proposed. For example, the transmission apparatus adjacent to the failure development location performs a mask control on alarms notified to the management apparatus to carry out a control so that the management apparatus is not notified of the alarms, or a management that utilizes polling with respect to the managed apparatuses is restricted in accordance with a situation of loads in a network to reduce the loads in the network.
Related techniques are disclosed in, for example, Japanese Laid-open Patent Publication No. 2010-124428 and Japanese Laid-open Patent Publication No. 9-282252.
However, according to the above-mentioned techniques, a transmission apparatus other than the transmission apparatus adjacent to the failure development location does not perform the mask control and thus notifies the management apparatus of the alarms such as the AIS or the RDI, for example. Since these alarms do not uniquely identify the development location of the failure, a prompt identification of the development location of the failure is interfered. In addition, the transmission apparatus adjacent to the development location of the failure holds back, by the mask control, the notification of the alarm that identify the development location of the failure such as the LOS, for example. For this reason, it is significantly difficult to identify the development location of the failure.